WHAT IS WRONG WITH THE WORLD TODAY Working with a partner brainstorm as many environmental problems as possible. Think about things that see or hear on the news that not only affect us but all living things. Remember that all living things in nature are connected so overlapping problems are ok.

Chapter 6: Humans in the Biosphere 6-1 A Changing Landscape

A Changing Landscape Earth as a Island –Human population is growing, but the Earth is not. –We are increasing demands on air, H20, and land. Human Activities –We use as much energy as all other multicellular species combined. –Humans change the flow of energy and reduce ecosystem’s ability to recycle.

Hunting and Gathering People were nomads, traveling to take advantage of movement and cycles of animals and plants. Subsistence Hunting: taking only necessities, and making few demands on the Earth. Ways the nomads changed the environment: 1.Build dams 2.Burned Grassland 3.Caused mass extinction of large animals

Agriculture Farming gave humans a dependable source of food. –Allowed humans to stay in one place. –Lead to the formation of towns and cities. Domestication of Animals –Pros: milk, meat, hides, wool, companionship, energy to do work –Cons: overgrazing, soil erosion, H2O supply strain

The Green Revolution Green Revolution: 1950’s, new intensive farming practices to increase crop yield. Monoculture: large fields were cleared and planted with a single crop year after year. Pros of Green Revolution –More food, “miracle strains”, larger equipment and machinery. Cons of Green Revolution –Deplete H2O and energy, pest reproduction, fertilizer interferes with food webs.

Industrial Growth and Urban Development Industrial Revolution: 1800’s, addition of factories and machines to civilation Effects of Industrial Revolution –Use of more fossil fuels –Production of waste Suburban Sprawl: living around cities –More stress on plants and animals

6-2: Renewable and Nonrenewable Resources Common Resource: “owned” by many people. Tragedy of the Commons –Common resources will be eventually destroyed because no one is responsible for preserving it.

Sustainable Use Renewable Resources: can be replenished or regenerated but not unlimited. Ex: trees and water Nonrenewable Resource: cannot be replenished Ex: fossil fuels, old-growth forest Sustainable Use: way of using natural resources at a rate that does not deplete them Ex: using lady bugs to eat pests instead of pesticides.

Land Resources Food crops grow best in soil that is a mixture of humus, sand, clay and rock. Plowing removes the roots of grasses that hold soil in place –Increases the rate of soil erosion Desertification: Combination of drought, farming, overgrazing turns areas into deserts

Land Resources Ways we guard against soil erosion: –Contour plowing –Leaving stems/roots of previous year’s crop –Planting rye instead of leaving field bare –Irrigation systems –Wind breaks

Invasive Species

Forest Resources Ways in which forests provide ecological services –Take out CO2, provide O2 –Products (wood, paper, lumber, fuel) –Store nutrients –Provide habitats food for organisms –Limit soil erosion

Forest Resources Old-growth Forest: never have been cut –Nonrenewable b/c takes centuries to grow back Deforestation: loss of forest –Soil erosion –Laterite: soil that has been chemically change to a hard brick-like material

Ocean Resources Over fishing: fish are harvested faster than they can reproduce; leads to destruction of fisheries Ex: cod, salmon, herring, king crab Aquaculture: farming of aquatic organisms

Water Resources Water is renewable, but the supply is limited Ways to ensure the sustainable use of water: –Protect systems involved in H2O cycle Ex: wetlands purify water –Preserve forests and vegetation

Air Resources Smog: a mixture of chemical the occurs as a gray-brown haze in the atmosphere. –Caused by car exhaust, industrial emissions, and burning fossil fuels. Particulates – microscopic particles of ash and dust Acid Rain: water mixes with nitrogen and sulfur gases to form acid rain

Invasive Species

6-3: Biodiversity Biodiversity: sum total of genetically based variety of all organisms Human threats to biodiversity: –Altering habitats –Hunting to extinction –Pollution –Introducing foreign species to new environments

Conserving Biodiversity Conservation: wise management of natural resources (preservation of habitats and wildlife) Ecological Hotspot: where habitats/species are in immediate danger of extinction

6-4 Charting a Course for the Future Two major global changes 1.Global Warming 2.Ozone layer depletion – protects from UV radiation Overexposure to UV radiation can cause cancer. The major cause of ozone depletion is CFC’s Ex: aerosol cans, Styrofoam, coolants in fridge